Circuit breaker



H. l. MADDEN CIRCUIT BREAKER Aug. 16, 1949.

Filed Oct. 15, 1945 INVENTOR Henryf Ma c/den.

- BY fl 4M WITNESSES:

Patented Aug. 16, 1949 CIRCUIT BREAKER I. Madden, Pittsburgh, Pa., assignon to W s in house; El ctric rnet t East P tts:

harsh. P's-f h ehrhd e Pehnsr v'ehie Application (lotober. 15, 1945, Serial No. 622,469 29 Clair ns (01. 2007108),

This invention relates to circuit breakers, and more par ul l to verl ad ip, devi es, o controlling automatic operation of circuit breakers.

One object of the invention is to provide a cirit bre r em odyin a mp e d le r mhenetie t ip. d vice n w ic a, sealed ca n o s t ming a body of fluidand a meenetizabi member within the casin moves o t ip t e r a er while the magnetizable member is, restrained from movin -by enersization of the e e troma netn ther obje t of the inve t on is o provide a circuit breaker with. an. imnrcved lee lhhles: netic tr-ip device embodyin a o el im d ay device wherein a magnetizable member Within a sealed casing containing a body offluid is restrained against movement while the. casing is moved to trip the breaker.

hnother object of the invention is to provide a circuit breaker with a novel trip means embodying a time delay device wherein a core me ber 'within a sealed'casing containing 'a body of fluid is restrained against movement while the casing'is'rnoved in one direction to eifect tripping of the breakerafter a time delay and in which the casing is moved the opposite direction to instantaneouslytrii) the breaker.

Ah a qhieei 9'? h' ih h hh is to provide ch breath? w th a metal he device hedv s a eeles asin weenie he e t u a the i w i h rmat re moves the ases t in t breather Wh l th e her erh te s hih ae ih t ihszvemeht b he ma netic t me, e rel rate 9? 3 W?- ihehi i the et ihe.

heath r o ih t e t e nvehtie is to. rovi e a circuit breaker embodying a novel trip device ttesting t e pregfliipg netaemhh wh rei a al e i prev-ti t r hi 'qf is. the new r fluid ea t as im h Th navel featu s tha e eeh e h e teristic of the invention are set u hr n the anrehqe elehhsthe ihreht t e however, both a to s ruhthre ehsi Qeehahha FQ eether with addit ona Qhieh s an eclvehte thereof, will be best understood front the follow: ins detailed de iip en o s e emb im nt ere: of when read in conjunction with th accompany in drawing; in w ich:

Figure 1 is a side elevational view, partly in section, of a circuit breaker embodying the invention;

Fig. 2 is a fragmentary e1evational view show: ing the member which trips the breaker rfi alilr 2 less of the direction of movement oi the core ruc ure- Rig. 3 is a fragmentary front elevational vie vg h me han m hown in me 4 is ah eeh see euel viewe he vein: me h m r c ht hi et e ho i 31 .1 "A fi sealed tube.

Re n t i ur l of the sta i the rit i en e nume l n igna a s f st be. 1h ti-ne m te ia which su po ts he v r us pe ts of the circuit breaker. A pair of terminals l 3 ud l5 are suitably secured to the base and each terminal has. o r or ehhhec he tasi L hich xten throu h th ac o th hate the 32 ele ri a co n t t reak to. the e imit? which t con r s.

Th u p m n 3, h a ontact b1 5 of ri d onduct n ma r e e ed. the ethi hd a ri d con a block 3 cured t0 th hese is e ect ca ly enm s t e ower termi a it through t e n r z ng wi d o h is dQYiQe 0f the break r w h w e her ina r is-f scribed.

The co means an me hanism i: h 2

, cuit breaker illustrated are similar to the circuit breaker fully disclosed in Patent No. '2 21 i,f1 7;1 issued September 10, 19 41), to Leon 3;. Ludwig and Merle E. Horn, and assigned to the assignee of the present invention. Hence only a brief de sc in ion of these parts w l be ven in @1 Q9:

plication.

The main stationary contacts and 21 are rigidly secured to the contact blocks 2-! and 2;, respectively; and the auxiliary stationary con; es s 28 and 3 are s cur d o t iane lerl w shaped contact platform 33 of conducting mate: rial which is mounted on the upper portion of the. block or mited t in n ki me e: men y mea s of n 35 pmil tihe fr m the opposite sides of the platform which engage in slo s 1 pr vid i a a o d Well 39 s h rfli to the block 2!, The platform 33 is biasedout wardly irorn the base I l a plurality of sprix s 4! and 4. a o rd mh m h 0f t i tform is limited by the engagement of thepins 3b with the outer ends of the slots 3] and by stop roiections carried bythe platform adja cent its upper end. The platforrn 33 and, conseguently, the auxiliary contacts 29 and 3| ar electrically connected to the terminal is by means of a flex heet whet e 1 'Ehe rnoyable contact means of the circuit breaker comprises a channel-shaped Contact arm 49 91 ee elhhhh lilhi iia w is rigidly em d to. a pivq es switch meihher'i hi eh fi h plurality of screws 53. The contact arm 49 carries a main contact bridging member 55 for bridging the main contacts 25 and 21, and an auxiliary contact member 51 for engaging the stationary auxiliary contacts 29 and 3|, the auxiliary contact members 51 being secured to the upper end of the channel-shaped contact arm is by a plurality of screws 59.

The main contact bridging member 55 is formed of rigid conducting material, and is loosely mounted on the contact arm 49 for limited movement relative to the contact arm toward and away from the main contacts 25 and 2'! by means of a pair of studs 5| secured to the contact carrying arm 49, only one stud being shown. A pair of coil springs (not shown) encircle the studs 6|, and are disposed between the contact carrying arm 49 and the bridging member 55 for biasing the bridging member toward the stationary main contacts 25 and 21 with a predetermined force. The ends of the bridging member 55 are beveled to lie parallel with the beveled edges of the contact blocks 2| and 23, and have a pair of contacts 61 secured thereto for engaging the main stationary contacts 25 and 21.

The auxiliary contact member 51 is formed of rigid conducting material, and has an intermediate contact 69 and an arcing contact secured thereto for engaging the intermediate and arcing contacts 29 and 3| of the stationary contact means.

A flexible shunt conductor 13 electrically connects the auxiliary contact arm 49 to the main stationary contact block 23. The flexible conductor 13 has its upper end secured to the contact arm 49 by the lower bolt 59. The lower end of the flexible shunt conductor 13 is secured to the lower contact block 23 by means of a bolt TI.

The switch member 5 I has a yoke-shaped lower end which is pivotally mounted between the side Walls of a main frame 19 by means of the pivot pin 8|. The switch member 5| is movable about its pivot axis to open and closed circuit positions to open and close the contact means of the breaker by means of an operating mechanism indicated generally at 83,.

The operating mechanism 83 is supported y the main frame 19 and comprises an actuating lever 85 pivoted on a pin 8'! carried by the frame, and is connected to the switch member 5| by a link 89. An operating member 9| is also pivoted on the pin 8! for movement about the same axis as the actuating lever 85. The actuating lever 85 is normally and releasably connected to the operating member 9| for movement thereby by means of a pair of latches 93 and 95, which are pivotally mounted on the lever 85 at 91 and 99, respectively. The latch 93 engages a roller I 9| carried by the operating member 9|, and this latch is, in turn, held in latching position by the auxiliary latch 95. The operating member 9| is adapted to be releasably held in closed circuit position by means of a main holding latch I03 pivoted at II9, which releasably engages the roller Hill. The auxiliary latch 95 is provided with a curved tailpiece I85 by means of which it is released to cause release of the latch 93 and consequent tripping of the circuit breaker by the release of the actuating lever 85 from its connection with the operating member 9|. When released the actuating member 85 moves in a counter-clockwise direction about the pivot axis 81, causing opening of the movable contact means. During this movement, a cam surface II" of the lever 85 engages the nose of the main holding latch I03, moving the holding latch to released position to effect release of the operating member 9|. The switch member 5| and the actuating lever are biased to open position by means of a pair of accelerating springs I89 (only one being shown), which are connected at their upper ends to the switch member 5| and at their lower ends to the sides of the main frame I9.

To close the circuit breaker after it has been tripped open, the operating membr 9| is first moved in a counterclockwise direction about the pivot axis 81 to the open position to eifect resetting of the latches and reestablishment of the releasable rigid connection between the actuating lever 85 and the operating member 9|. After the rigid connection is thus established, the operating member 9| is moved in a clockwise direction to closed position by means of a handle III to efiect closing of the contact means of the breaker. The clockwise or closing movement of the operating member 9| is limited by a portion 92 thereof striking a fixed stop 94 on the frame '59. When the parts have been moved to closed position, the main holding latch I03 reengages the roller |9| to hold the operating member in closed position. The stop 94 is located to permit a slight overtravel of the member 9| to insure proper engagement of the latch I83 with the roller IOI. It will be noted that the construction of the operating mechanism is such that the movable contact means is trip-free of the operating member 9|; that is, when the breaker is tripped, the contact means move to open position irrespective of the position of the operating member 9|.

The mounting arrangement of the contact means is such that during opening of the breaker the main bridging member 55 is first separated from the stationary contacts 25 and 21, while the auxiliary contacts remain in engagement by reason of the outward movement of the contact platform 33 under the influence of the biasing springs 4| and 43. After the bridging member 55 has separated a predetermined distance from the main stationary contacts, the intermediate contacts 29 and 59 begin to separate. This takes place as soon as the pins 35 engage the ends of the slots 31. During this time, the arcing contacts 3| and II remain in engagement due to the rocking movement of the contact platform 33. After the intermediate contacts have separated a predetermined distance, the arcing contacts 3| and II begin to separate. During closing, the contacts engage in the reverse order, as will readily be understood. It will thus be seen that the are formed during separation of the contacts is drawn only between the arcing contacts 3| and II.

The circuit breaker is adapted to be tripped open either manually, or automatically, in response to predetermined overload conditions in the circuit, by means of a trip mechanism indicated generally at H5.

The trip mechanism comprises a trip lever I" which is pivotally mounted intermediate its ends on the frame I9 by means of a pivot pin H9, and an electromagnetic trip means, indicated generally at |2|, which is operable in response to the predetermined overload conditions to move the trip lever Hi to tripping position to cause automatic opening of the circuit breaker.

One arm I23 of the trip lever II! is offset and extends inwardly toward the base I I of the circuit breaker, and has its inner end disposed immediately above the trip means IZI to be engaged and moved by a trip rod I 95 to efiect automatic tripping of the breaker. The arm I23 of the trip lever is provided with a projection I25 which is adapted to engage the curved tailpiece I05 of the auxiliary latch 95 to move this latch to released position upon movement of the trip lever to tripping position. The other arm of the trip lever I I1 forms a handle I21 whereby the trip lever may be manually moved to tripping position to efiect manual opening of the circuit breaker. A spring I29 connects the arm I23 of the trip lever II1 to an extension of the main holding latch I03 so that the spring thus serves to bias the main holding latch to latching position and the trip lever to its normal inoperative position, as shown in Fig. 1.

The electromagnet I2I comprises a stationary core member I3I, a movable core structure I33 having a, trip member I355 related thereto, and an energizing winding I31 having one end connected to the contact block 23 and the other end connected to the terminal I5.

The stationary core member I3I is secured to the base II by means of screws I39 which pass through openings in the base and engage threaded openings in formed over projections MI and I43 of the core member I3I. The lower projection I43 of the fixed core member is again formed outwardly as at I45 to serve as a support means for the movable core structure I33.

The movable core structure I33 comprises a sealed casing I41 containing a body of oil or other liquid of suitable viscosity, a main core member I49 and a secondary core member I 5|. The main core member I49 is tubular and has its upper end closed by an integral part which is tapped to receive the threaded upper end of an adjusting rod I53 which extends downwardly through an opening in the projection I45. A spring I55 is disposed between a washer I51 surrounding the rod I53 and a collar I59 integral with or suitably secured to the rod I53. The bottom "SI of the sealed casing I41 rests on the upper end of the rod I53. The spring I55, therefore, by Supporting the rod. I53, resiliently supports the entire movable core structure to permit the core structure to move downwardly for a purpose to be fully described later.

The secondary core member I5I is normally maintained in the upper end of the sealed casing I41 by means of a spring I53 compressed between the bottom IEI of the sealed casing and a shoulder on the core member I5I. The secondary core member I5I is provided with an opening extending axially therethrough, through which extends a control tube I65 of nonmagnetic material. At its lower end the tube I65 rests on the bottom portion IEI of the sealed casing and is provided with an opening I61 for the passage of fluid. The upper end of the control tube I55 is provided with a valve chamber I69 rigidly secured thereto disposed in nested relation, an enlarged opening I1I in the upper end of the core member 15!, the opening I1I being somewhat larger in diameter than the valve chamber I99 to provide an oil passage by-passing the valve chamber.

The upper end of the sealed casing I41 is closed by a cap I13 suitably secured as by brazing to the body of the casing so as to hermetically seal the casing. The cap I13 is provided with a centrally located tapped opening and a short filler tube I14 for the purpose of filling the casing to the required level with fluid. After the casing H1. is filled with fluid to the required level, the

opening is sealed by inserting a screw I15 therein and brazing or soldering the screw in place.

The upper end of the valve chamber I69 is closed by means of a disc I11 (Fig. 4) suitably secured thereto as by brazing, the disc being providcd with a plurality of orifices I19. The disc I11 rests against the inner end of the filler tube I14 to prevent movement or the control casing I35 relative to the sealed casing I41. Disposed in the valve chamber I 69 is an inverted cupshaped valve I8I biased by means of a spring I93 to a closed position against the bottom of the valve chamber. The valve I8I is provided with an orifice I but the rim of the valve biased against the bottom of the chamber I69 forms a seal. The valve I8I fOrms a seal for the upper end of the control tube I65 except for the orifice I85. A valve disc I81 disposed within the space below the valve I8I is biased downwardly by the force of gravity and crimped at several points about its edge as at I89 to permit fluid to flow thereunder and through the orifice I85 in the valve I8I. In addition to the opening I61 at the lower end of the tube I65, the tube is provided with a large opening I 9I (Fig. 4) spaced a predetermined distance below the chamber I69 and a small orifice I93 located just below the bottomof the valve chamber for controlling the flow 01. fluid as will be more fully brought out later in the description of the operation of the device.

The sealed casing I41 is adapted to be moved upwardly under one set of conditions and downwardly under another set of conditions to effect tripping of the breaker. To accomplish this, the trip member I35 must operate to actuate the trip rod I95 upwardly to actuate the trip lever I I 1 when the casing I 41 moves in either direction. The trip rod I95 extends vertically through an opening in a cross member I91 of the main breaker frame 19 and is provided with a collar I99 integral therewith for normally retaining the trip rod in the position shown. The lower end of the trip rod I95 is provided with a head 20I which is adapted to be engaged by a projection 203 on the righthand end (Figs. 1, 2 and 3) of the trip member I35. The trip member I 35 is supported in a bracket 205 secured by means of screws 201 to the top of the fixed core member I3I (see Figs. 2 and 3). The bracket 205 is provided with upwardly extending ears 209 each having an inwardly extending pin 2II secured therein. These pins extend through elongated slots 213 (Fig. 2) in ears 2I5 formed downwardly from the trip member I35. The lefthand end (Figs. 1 and 2) of the trip member has a down ward reverse bend 2I1 which extends underneath a projection 2I-9 of the cap I13 on the upper end of the sealed casing.

The trip member I35 is provided with a clearance opening for the screw I15 and normally rests on the flat top surface of the cap I13 so that upon upward movement, the casing I41 car ries the trip member bodily therewith to actuate the trip rod I95. During this movement, the slots 2I3 move freely over the pins 2i I. When the sealed casing I41 moves downwardly, as will be hereinafter described, the projection 2I9 on the cap I13 engages the bent portion 2I1 of the trip member I35 and rotates the trip member counterclockwise about the pins 2 to engage the projection 203 with the trip rod I95 to efiect tripping of the breaker.

The trip device functions to trip the breaker after a comparative long time delay in response to overload currents in the lower range of overload current values, with a short time delay in the intermediate range of overload currents up to a predetermined value and instantaneously in response to overload currents above said predetermined value or on short circuits. These ranges of overload current values may be arbitrarily defined as follows: The low range between 100% and 700% of normal rated current; the intermediate range from 700% to 1000% of normal rated current and instantaneous 1000% or more of normal rated current or short circuits.

' Upon the occurrence of an overload current in the lower range of overloads, that is, up to 700% of normal current, the secondary core member II starts to move downwardly forcing oil through the control tube I65 out of the orifice I93 and between the valve chamber I69 and the wall of the opening I'II into the upper portion of the sealed casing above the core member. The upward pressure of the oil in the tube I65 raises the disc I81 against the bottom face of the valve I 8| closing the orifice I85 but this pressure is insufficient to compress the spring I83 and open the valve I8I. The downward movement of the core member I5I compresses the spring I63 and biases the entire core structure downward against the spring I55 but the force is not great enough to compress the spring I55.

As the secondary core member I5I continues itsdownward movement, it slowly reduces the magnetic air gap between itself and the main core member I 49. After moving downwardly a predetermined distance the core member I5I uncovers the opening I9I in the tube I65 permitting a free fiow of oil past the core member I5I which now increases its downward speed to rapidly close the air gap between the two core members I49 and I5I and at the same time open an air gap between the core member I5I and the upper leg of the fixed core member I3I. The entire core structure now acts as in a solenoid and is moved upwardly to trip the breaker.

When the circuit is interrupted, by opening of the breaker contacts, the winding I31 is deenergized permitting the entire core structure to drop to its original position. The spring I63 now moves the secondary core member I5I upwardly in the sealed casing I41 forcing oil to flow downwardly through the control tube. The downward pressure of the oil through the orifices I19 and I85 (Fig. 4) causes the valve disc I81 to move downward opening the orifice I85 and permitting free fiow of oil to thereby permit the spring I63 to quickly restore the core member I5I to its uppermost position in the sealed casing.

When an overload occurs in the intermediate range of overloads between 700% and 1000% of normal rated current the force with which the secondary core member I5I is attracted downward is much greater due to increased energization of the winding I31. This forces the oil upwardly through the tube I65 with sufiicient pressure to cause opening of the valve I8I and permits a greater flow of oil to the upper part of the sealed casing. The rate of movement of the secondary core member I5I is thus increased and tripping is effected with a much shorter time delay than it would be if the valve I8I were not provided. Under this condition, the oil flows around the valve I8l and out the orifice in addition to the flow of oil through the orifice I93 and between the valve chamber I69 and the wall of the recess I1I. After the core'member I5I uncovers the opening I9Iin the control tube I65, the tripping action is the same as that described previously in connection with low range of overload currents.

When the winding I31 is energized inresponse to an overload current of 1000% or over of normal rated value, or a short circuit, the secondary core member I5I is attracted downwardly with such force and speed that the oil below the core member is unable to flow through the control tube I65 and, therefore, moves the entire core structure including the sealed casing I41 downwardly to trip the breaker. The downward movement of the sealed casing engages the projection 2I9 of the cap I13 with the bent portion 2I1 of the trip member I35 and rocks the trip member counterclockwise to actuate the trip rod I95 and instantaneously trip the breaker. The downward tripping movement of the core structure compresses the spring I55 which, upon deenergization of the winding I31, reacts to restore the core structure to its normal position as shown in Fig. 1.

Means is provided to vary the minimum current required to trip the breaker. This means comprises the rod I53 which thre'adedly engages the main core member I49. By turning the rod I53, the main core member I 49 may be moved away from or nearer to the secondary core member I5I thus increasing or decreasing the initial air gap between the core members, depending upon which direction the rod I53 is turned, without changing the tension of the sprin I55.

Certain features are disclosed but not claimed in the instant application which are fully disclosed and claimed in copending application Serial No. 623,124, filed October 18, 1945, by A. H. Baylis and H. L. Rawlins and assigned to the assignee of the instant invention.

From the foregoing description, it will be apparent that there is provided a novel trip device for a circuit breaker wherein a solenoid is operated in one direction to trip the breaker after a time delay and in the opposite direction to instantaneously trip the breaker. The time delay feature is hermetically sealed in a casing so' as to prevent corrosion of the moving parts of the time delay device and to prevent entrance of foreign substances into the sealed tube.

Having described the invention in accordance with the patent statutes, it is to be understood that various changes and modifications may be made in the structural details and combination of elements disclosed without departing from some of the essential features of the invention. It is, therefore, desired that the language of the appended claims be given as reasonably broad interpretation as the prior art permits.

I claim as my invention:

1. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device operable to cause automatic operation of said operating mechanism comprising an energizing winding, a sealed casing disposed in the mag.- netic field of said winding and movable in one direction to trip said operating mechanism, an armature disposed in the magnetic field outside of said casing and operable upon energization of said winding to move said casing, and time delay means disposed within said casing and biased to provide an air gap, said means being movable in the opposite direction upon energization of said winding to reduce said air gap, and said armature being operable when said. air gap is reduced a predetermined amount :to move .said easing .-=to said operating mechanism.

2. :a circuit breaker comprising relatively movable JCQEtaCt means and operating means therefor, the combination of a trip member operable ltolcause operation of said operating means, :an electromagnetic trip device for operating said :trip member comprising an energizing winding, rarsealed .casing containing a body .of fluid movable (to :trip .said :trip member, .an armature -.operable upon energization of said winding to move :said casing, time delay means comprising a magnetizable member -within said casing biased :to .provide a magnetic air gap, said magnetizable member being movable upon .energization of said winding to reduce said :air gap, means disposed in said casing and (movable therewith tor :conitrolling the rate of reductionof said air gap, and said armature :being operable when said air gap has been reduced a predetermined amount to move said casing to trip said trip member.

:3. In :a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip member on 'erable to cause operation of said operating :mech- :anism, an electromagnetic tripidevice for operating said trip member comprising a sealed casing containing a lbQdyzOf :fluid movable to.operate said :trip member, an armature movable intone direcition in :response to (overloads below a wpredeterrmined value to :move said casing, :time .delay means comprising a magnetizable member disposed within said casing and operable in :the opiposite :direction :to delay operation of said :armature, said armature and said :magnetizable memher being movable in response to overload currents above said predetermined value to .move said casing in the opposite direction to thereby instantaneously--operate said trip member.

4. In a c'ircuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip member operable to causeoperation-of saidoperatingmechanism a trip device for operating said trip member comprising an energizing winding, a sealed casing movable in-one direction when said wind- 'ing is energized in response :to overload currents below a predetermined value, said casing being movable in another direction when said winding is energized =byoverload currents above said predetermined value, and means operable by said casing irrespective of the direction of movement of said casing to operate said trip member.

5. -In'a circuit breaker =comprising relatively movable contacts and operating mechanism therefor, the combination-of :a trip member oparable :to'cause operation of said operating mechanism, atrip device for operating-said trip member comprising an energizing winding, a core structure comprising a sealed casing movable in one direction 'to operate said trip member'after atime delay and movable inanotherdirection to instantaneously operate said trip member, means-operable by said casing when said casing is moved in either direction to -operate said trip member, and time delay means for delaying movement of said casing in said one direction.

'6. :In a circuit breaker comprising relatively movable contacts and operatingmechanism-therefonthe combination-of a tripdevice-comprising an energizing winding, asealed casing movablein one direction rto trip. said operating mechanism i after a "time ,delay, said oasing being movable -in anotheridirection :to instantaneously trip the breaker, means {operable in response to lenergization 10 of said winding to move said casing, means dislposed within said casing operable :to delay movement .of said casing in said .one direction, and means operable by said casing irrespective .of .the direction of movement of said casing to .trip said operating mechanism.

7. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of an electromagnetic trip device :comprising an energizing winding, a sealed casing movable "in one direction upon energization of said winding to cause tripping of said operating mechanism after a time delay, said casing being movable in another direction to cause instantaneous tripping of said operating mechanism, means comprising a magnetizable member within said casing biased to provide a magnetic air gap, said magnetizable member :being operable upon onergizationof said winding to reduce said air gap, means responsive to energi-zation of said winding when said air gap 'has been reduced a predetermined amount to move said casing in said one direction, and means operable by the casing when said casing is moved in either direction to trip said operating mechanism.

*8. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, therein combination of an electromagnetic trip device operable to cause operation of said operating mechanism comprising an energizing'winding, asea-ledcasing containing a body of fluid, saidcasing being-movable in one direction to trip said operating mechanism after a time delay and in another direction to instantaneously trip said-operating mechanism, an armatureoperable upon-energization of said winding to move said 'casing in said one direction, time delay uneans comprising a magnetizable member within said casing biased to provide an air gap, said magnetizable member being movable *upon energization of said winding to reduce said air gap, means movable :with said casing for controlling displacementof fluidfrom one end of said casing to the other to retard movement of said magnetizable member, and an armature operable when said air gap has been reduced a predetermined amount to move said casing in said one direction.

9. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of an electromagnetic trip device operable to :cause operation of said operating mechanism comprising an energizing winding, a movable core structure comprising a sealed --'CaSillg containing a body of fluid, said casing being movable in two directions to trip said operating mechanism, an armature operable when the winding :is energized by overload currents below a predetermined value to move said casing-in onedirectionto-trip said operating mechanism after a time delay, -a magnetizable member within said casingmovable in response to energizationof said winding by overload currents below said "predetermined \value to delay movement of saidicasing by saidarmature, said magnetiza-ble :member being operable in response-to overloadcurrents above, said predetermined value t0;m.0.ve said .wcasing in another :direction to instantaneously strip ,said operating mechanism, and means operable'byisaid casing -whensaid casing-moves in either direction .to effect tripping of said operating mechanism.

110. :In -.-a circuit tbreaker comprising relatively movable .contacts and operating mechanism therefor, the combination of an electromagnetic trip device operable to cause operation of said operating mechanism comprising an energizing winding, a movable core structure comprising a sealed casing containing a body of fluid, said casing being movable in two directions to trip said operating mechanism, an armature operable when the winding is energized by overload currents below a predetermined value to move said casing in one direction to trip said operating mechanism after a time delay, a magnetizable member within 'said casing movable in response to energization of .said winding by overload :currents below said predetermined value to delay operation of said casing by said armature, valve means movable with said casing for controlling movement of said magnetizable member, said magnetizable member being operable in response to overload currents above said predetermined value to move said casing in another direction to instantaneously trip said operating mechanism, and means operable by said casing when said casing moves in either direction to efiect tripping of said operating mech- 'anism.

' member within said casing movable in response to energization of said winding by overload currents below said predetermined value to delay operation of said casing by said armature, means comprising a control tube movable with said sealed casing for permitting flow of fluid from one side of said magnetizable member to the other, means in said control tube for controlling the flow of fluid to control the rate of movement of said magnetizable member, said magnetizable member being operable in response to overload currents above said predetermined value to move said casing in another direction to instantaneously trip said operating mechanism, and means operable by said casing when said casing moves in either direction to effect tripping of said operating mechanism.

12. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device operable to cause automatic operation of said breaker comprising an energizing winding and a movable core structure movable in two directions to trip said operating mechanism, said movable core structure comprising a sealed casing, an armature operable to move said core stnu-cture in one direction to trip said operating mechanism after a time delay, time delay means comprising a core member disposed within said casing and operable in response to overload currents below a predetermined value to delay operation of said core structure in said one direction, said core member being operable in response to overload currents above said predetermined value to move said core structure in the other direction to'instantaneously trip said operating mechanism.

13. In a circuit breaker comprising relatively movable contacts and operating mechanism "therefor, the combination of a trip device onerable to cause automatic operation of said breaker comprising an energizing winding and a movable core structure movable in two directions to trip said operating mechanism, said movable core structure comprising a sealed casing, an armature operable to move said core structure in one direction to trip said operating mechanism after a time delay, time delay means comprising a core member disposed within said casing and operable in response to overload currents below a predetermined value to delay operation of said core structure in said one direction, said core member being operable in response to overload currents above said predetermined value to move said core structure in the other direction to instantaneously trip said operating mechanism, and means operable by said movable core structure when said core structure is moved in either direction to trip said operating mechanism.

14. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device operable to cause automatic operation of said operating mechanism comprising an energizing winding, a sealed casing disposed in said winding and movable to trip said operating mechanism, an armature operable upon energization of said winding to move said casing to trip said operating mechanism, time delay means comprising a core member within said casing biased to provide an air gap, said time delay means being operable upon energization of said winding to reduce said air gap, said armature being operable when the air gap is reduced a predetermined amount to operate said casing to trip said operating mechanism, and means within said casing mounted in fixed relation to said casing for controlling the rate of movement of said time delay means.

15. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device operable to cause automatic operation of said operating mechanism comprising an energizing winding, a sealed casing movable in two directions to trip said operating mechanism, an armature energized by said winding under certain conditions to move said casing in one direction to trip said operating mechanism, time delay means comprising a core member in said casing providing a magnetic air gap and movable relative to said casing to reduce said air gap, said armature being operable when said air gap is reduced a predetermined amount to move said casing in said one direction, means within said casing mounted for movement with said casing for controlling the rate of movement of said core member, said core member being operable under certain other conditions to move said casing in another direction to instantaneously trip said operating mechanism.

16. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device operable to cause automatic operation of said operating mechanism comprising an energizing winding, a movable core structure movable in two directions to efiect tripping of said operating mechanism, means resiliently supporting said core structure, said core structure comprising a sealed casing, an armature operable to move said core structure in one direction to trip said operating mechanism after a time delay, time delay means comprising a core member within said casing, spring means biasing said core member to provide a magnetic air gap, said core member being movable relative to said casing in response to overload currents below a predetermined amount to reduce said air gap, said armature being operable when said air gap has been reduced a predetermined amount to move said core structure in said one direction, said core member being operable in response to overload currents above said predetermined value to move said core structure in another direction against the force of said resilient means to instantaneously trip said operating mechanism.

17. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device perable to cause automatic operation of said operating mechanism comprising an energizing winding, a movable core structure movable in two directions to effect tripping of said operating mechanism, means resiliently supporting said core structure, said core structure comprising a sealed casing, an armature operable to move said core structure in one direction to trip said operating mechanism after a time delay, time delay means comprising a core member within said casing, spring means biasing said core member to provide a magnetic air gap, said core member being movable relative to said casing in response to overload currents below a predetermined amount to reduce said air gap, said armature being operable when said air gap has been reduced a predetermined amount to move said core structure in said one direction, said core member being operable in response to overload currents above said predetermined value to move said core structure in another direction against the force of said resilient means to instantaneously trip said operating mechanism, and means operable by said movable core structure when said core structure moves in either direction to trip said operating mechanism.

13. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of an electromagnetic trip device operable to cause automatic operation of said operating mechanism comprising an energizing winding, a sealed casing containing a body of fluid and movable to trip said operating mechanism, an armature operable when the winding is energized by overload currents below a predetermined value to move said casing to trip said operating mechanism, a magnetizable member within said casing movable upon energization of said winding to delay movement of said casing, valve means movable with said casing for controlling movement of said magnetizable member, said valve opening in response to certain overload current conditions below said predetermined value to reduce the time delay action of said magnetizable member.

19. In a circuit breaker comprising relatively movable contact means, the combination of a trip device operable to cause automatic opening of said contact means, said trip device comprising an energizing winding, a movable core structure movable in two directions to effect tripping of said operating mechanism, said core structure comprising a sealed casing containing a body of fluid, an armature operable upon energization of said winding to move said core structure in one direction to trip said operating mechanism after a time delay, time delay means comprising a core member within said casing for restricting displacement of fluid to retard tripping movement of said casing in said one direction with a relatively long time delay, valve means operable to increase the rate of displacement of fluid to thereby retard tripping movement of said casing in said one direction with a relatively short time delay, and said core structure at times being movable in another direction to instantaneously trip said operating mechanism.

20. In a circuit breaker comprising relatively movable contact means, the combination of a trip device operable to cause automatic opening of said contact means, said trip device comprising an energizing winding, a movable core structure movable in two directions to effect tripping of said operating mechanism comprising a sealed casing containing a body of fluid, an armature operable upon energization of said winding to move said core structure in one direction, time delay means comprising a core member disposed within said casing for restricting displacement of fluid to retard tripping movement of said casing in said one direction with a relatively long time delay in response to overload currents below a predeter mined value, valve means operable in response to overload currents above said predetermined value to increase the rate of displacement of fluid to thereby retard tripping movement of said casing in said one direction with a relatively short time delay, and said core structure at times being movable in another direction to instantaneously trip said operating mechanism.

HENRY I. MADDEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,072,932 Wilckens Mar. 9, 1937 2,373,998 Burgwin Apr. 17, 1945 2,419,892 Graves Apr. 29, 1947 2,451,962 Lindstrom Oct. 19, 1948 

